To successfully lose weight, you must carry out a plan to balance your caloric intake with exercise. Ideally, dieting should be done by eating a nutritionally balanced, low-calorie diet and increasing physical activity.

Although there are many programs advertised to help you lose weight, the only proven long-term and safe method is to burn more calories than you consume.

This is achieved either by reducing the caloric intake (eat less food or healthier food) or by increasing the energy expenditure (exercise more). Often, behavior modification techniques like eating smaller portions are used to help control eating habits. Once the weight is lost, these habits can be modified slightly for weight maintenance.

If you have unintentional weight loss , it can be a symptom of various medical or psychiatric disorders, or it can be due to increasing your exercise or decreasing your food intake.

HEALTHY CALORIE INTAKE

The U.S. Committee on Dietary Allowance has published recommended energy intakes (number of calories) for various age and sex groups. These numbers also depend on your activity level and medical conditions, including pregnancy.

WEIGHT LOSS TIPS

One pound of fat contains approximately 3,500 calories, so to lose one pound a week, a person should consume approximately 3,500 fewer calories per week. This can be done by reducing the daily intake by 500 calories per day (500 x 7 days will provide a deficit of 3,500 calories per week). To lose 2 pounds per week, a deficit of 1,000 calories per day is required.

If this seems impossible, remember that physical activity also contributes significantly to weight loss. The deficit of 500 to 1,000 calories can come from a combination of increased physical activity and reduced intake on a daily basis.

Therefore, you don't need to experience significant food deprivation. The lowest intake per day recommended for women is 1,200 calories, unless they are in a medically-supervised, very low-calorie regimen which may have a daily level of 500 to 800 calories per day.

The lowest level recommended for men is 1,500 calories per day. A very low-calorie diet can also be used by males if they are in a medically-supervised program.

Tips for preventing weight gain:

Avoid foods that are high in fat and sugar.

Reduce how much alcohol you drink.

Avoid stress, frustration, and boredom.

If you are depressed, seek medical treatment.

Avoid a sedentary lifestyle by increasing your activity level:

Perform aerobic exercise for at least 30 minutes a day, 3 times a week .

A fad diet is one that makes unrealistic promises. Most fad diets are very low in carbohydrates and in calories, causing fluid loss from the body, which indicates a loss of weight on the scale. Once the body gets rehydrated with water, the weight will come right back.

Evaluation of a fad diet:

Is the diet medically and nutritionally safe? Get an opinion from a physician and a registered dietitian.

Red flags for fad diets include: overemphasis on a specific food group or groups, limited food choices, and a "calories do not count" approach.

These are ways to decide whether to use a diet or not. If there is no nutritionally or medically reliable information provided, and if there are no statistics to back the claims, then it is not a good diet to consider. Remember, if it sounds too good to be true, then it probably is.

SUMMARY

For weight loss to be successful, here is a summary of basic guidelines:

Aerobic physical activity will assist in increasing muscle tissue which will burn more calories. You should plan on 20-minute sessions at least 3 times per week.

Gradual changes in eating habits will help encourage a permanent lifestyle change.

A slow weight loss of 1 or 2 pounds a week, until the desirable body weight is reached, is best.

RESOURCES

A registered dietitian is an excellent resource for individualized weight loss. Dietitians can provide information on classes and programs available in the community.

By far, the most well-known community-based support group is Weight Watchers. Members meet every week and learn about healthy eating while encouraging each other in their weight loss goals.

Consumer brochures can be obtained from the Federal Trade Commission on evaluation of commercial weight loss programs.

Review Date: 8/8/2007Reviewed By: Cynthia Dennison Haines, MD, family physician specializing in nutrition, fitness, and preventive health, St. John's Mercy Medical Center, St. Louis, MO, and Assistant Clinical Professor, St. Louis University's School of Medicine, Department of Community and Family Medicine.